Field of the Invention
The present invention relates to a wireless communication system and, more particularly, to a method and apparatus for performing or supporting machine type communication (MTC).
Discussion of the Related Art
Machine type communication (MTC) refers to a communication scheme between one or more machines and is also referred to as machine-to-machine (M2M) communication. Here, a machine refers to an entity which does not require direct human operation or intervention. For example, examples of the machine may include not only a device including a mobile communication module, such as a meter or a vending machine, but also a user equipment such as a smartphone which is capable of automatically accessing a network without operation/intervention of a user to perform communication. Various examples of such a machine are referred to as an MTC device or terminal in the present specification. That is, MTC refers to communication performed by one or more machines (that is, MTC devices) without human operation/intervention.
MTC may include communication (e.g., device-to-device (D2D) communication) between MTC devices and communication between an MTC device and an MTC application server. Examples of communication between an MTC device and an MTC application server include communication between a vending machine and a server, communication between a point of sale (POS) device and a server and an electric meter, and communication between a gas meter or a water meter and a server. MTC-based applications may include security, transportation, healthcare, etc.
As compared to a person-to-person communication method, MTC may transmit and receive a small amount of data among a large number of devices. Additionally, MTC is performed according to a predetermined period or only when a specific event occurs and may be infrequently performed. In consideration of this, an MTC device may be normally set to an offline state to minimize power consumption. Alternatively, even when an MTC device is in an online state, a connection for data transmission/reception (e.g., an Internet protocol (IP) connection) may not be established in order to minimize system resource consumption. That is, an IP address of an MTC device may not be available by a server or may not be reachable. In this case, in order to perform MTC, signaling for requesting or instructing the MTC device to establish the IP connection is necessary and such signaling may be a trigger indication for an MTC device. However, up to now, a method of triggering an MTC device has not been provided.